my image's value are between 280 to 320

I have read an image (a temperature image which its pixels value are between 280 to 320) in MATLAB and after doing some operations in MATLAB I want to save this image and then read this image using another software but since this image's pixels value are between 280 to 320, when I save this image as .tiff format, all of the image become white. how can I save this image in a gray scale and in a way that pixels with the value 280 become black and pixels with the value 320 become white and the rest of the pixels lay between black and white?